White-light generation through Ce3+/Mn2+-codoped and Eu2+-doped Ba1.2Ca0.8SiO4 T-phase phosphors

Hexagonal Ba1.20Ca0.8−2x−ySiO4:xCe3+,xLi+,yMn2+ phosphors exhibit two emission bands peaking near 400 and 600 nm from the allowed f-d transition of Ce3+ ions and the forbidden 4T1-6A1 transition of Mn2+ ions, respectively. The strong interaction between Ce3+/Mn2+ ions is investigated in terms of energy transfer, crystal field effect, and microstructure by varying their concentrations. They show a higher quenching temperature of 250 °C than that of a commercially used (Ba,Sr)2SiO4:Eu2+ phosphor (150 °C). Finally, mixtures of these phosphors with green-emissive Ba1.20Ca0.70SiO4:0.10Eu2+ are tested and yielded correlated color temperatures from 3500 to 7000 K, and color rendering indices up to 95%.